Family History, Psychiatric Comorbidities Predict Tic Disorder Persistence Into Adulthood

Psychiatric comorbidities in childhood and family history of psychiatric disorders were found to be risk factors for tic disorder persistence in adulthood, according to study findings published in the journal Movement Disorders.

After age 12, tics in children typically begin to improve; however, some individuals continue to have significant tic-related symptoms and associated comorbidities that require specialized care.

Researchers evaluated the percentage of tic disorders in childhood that continued into adulthood, as well as the risk factors associated with tic disorder persistence.

Data were collected from various Swedish health registers of individuals with at least 1 diagnosis of a tic disorder identified between 3 and 17 years. Participants were divided into 2 cohorts: those with tic disorders persisting into adulthood and those with nonpersisting tic disorders.

The researchers also assessed potential risk factors, including sex, socioeconomic status, childhood psychiatric comorbidities, perinatal complications, presence of autoimmune disease, and family history.

Of 3,761 patients with childhood tic disorders eligible for study inclusion, 754 (20.05%) were found to have persisting tic disorders and the remaining 3,007 (79.95%) had nonpersisting tic disorders. The majority of patients in both groups were boys.

The researchers found that all psychiatric comorbidities diagnosed before age 18 were associated with tic disorder persistence. Attention-deficit hyperactivity disorder (ADHD) followed by pervasive developmental disorders (PDD) and obsessive-compulsive disorder (OCD) were the strongest predictors of tic disorder persistence into adulthood (odds ratios [ORs], 3.35, 2.80, and 2.71, respectively).

In addition, the researchers noted that a greater number of childhood psychiatric comorbidities was linked to a higher risk for tic disorder persistence.

Psychiatric disorders in first-degree relatives led to an increased risk for tic disorder persistence among study participants; the most significant associations were with family history of tic disorders and OCD (ORs, 2.04 and 2.02, respectively).

Multivariable analyses showed an independent association between variables — childhood ADHD, OCD, PDD, comorbid anxiety disorders, and family history of tic disorders and anxiety disorders — and tic disorder persistence.

The researchers did not observe significant associations of tic disorder persistence with socioeconomic status, perinatal complications, and autoimmune disease.

Study limitations included the lack of a measure for tic severity; potential surveillance bias, as the main reason for consultation during adulthood may not have been tic disorders; and the lack of generalizability to primary care settings and those with less severe disease. 

Overall, the researchers concluded, “Future studies would benefit from exploring additional variables to improve our understanding of tic disorder persistence.”